1. Field of the Invention
The present invention relates to a paper feeder of a label printer using an electronic photographic system which makes printing on a continuous printing paper on which a multiplicity of label papers are successively affixed.
2. Description of the Relative Art
There is known a label printer which can make printing successively on a continuous printing paper on which a multiplicity of label papers are successively affixed. When an electronic photographic system is adopted to this kind of label printer, toner attached on the label paper is thermally pressed by a fixing device using a heat roller. Accordingly, when the printing operation is stopped on the way, it is necessary to feed the printing paper forward by a predetermined length until a final printing position passes through the fixing device. Thereafter, when the printing operation is resumed, a process for the printing is made newly so that a blank portion is formed between the final printing position and the next printing start position on the printing paper, resulting in unused portion of the printing paper from the position of the heat roller to the position of the main charger being left blank.
A paper feeder of a non-impact transfer type printer disclosed in Japanese Patent Publication No. 56-5993 comprises a photosensitive drum which is applied with information to be printed, a retractor mechanism which causes the photosensitive drum to be brought into contact with the printing paper or be separated from the printing paper, a control circuit which controls to make equal the rotational speed of the photosensitive drum to the feeding speed of the paper when the photosensitive drum is in contact with the paper, and control means for moving back the printing paper by a predetermined distance in order to make the distance between the transfer completion end and the next transfer start end of the printing paper to a predetermined value when the photosensitive drum is separated from the printing paper, whereby the occurrence of blank printing paper is avoided when the printing is resumed.
In the label printer which makes the printing on the label paper having a fixed length in the longitudinal direction of the printing paper, it is a matter of course that it is necessary to move back the printing paper to a target position to eliminate blank paper and it is further necessary to set the printing resumption position to a predetermined position of the label paper exactly. In addition, since many functional portions including a roller mechanism for moving the paper, a fixing device, a transfer charger and the like are disposed in the traveling path of the printing paper and a length of the paper to be moved back is relatively long, it is very important to control the backward movement of the paper to a target position stably and exactly.
However, in the paper feeder of the non-impact transfer type printer disclosed in the above publication, since it is merely performed that the paper is moved back by a predetermined value in order to eliminate the vain paper, it can not be adopted in the label printer requiring high accuracy, reliability and stability.